def main():
    coordinates = list(map(float, input().split()))
    distance = ((coordinates[2] - coordinates[0])**2 + (coordinates[3] - coordinates[1])**2)**(1/2)
    print('{:.5f}'.format(distance))


if __name__ == '__main__':
    main()
 def main():
    coordinates = list(map(float, input().split()))
    distance = ((coordinates[2] - coordinates[0])**2 + (coordinates[3] - coordinates[1])**2)**(1/2)
    print('{:.5f}'.format(distance)) main coordinates = list(map(float, input().split())) coordinates list(map(float, input().split())) list map(float, input().split()) map float input().split() ().split () input split distance = ((coordinates[2] - coordinates[0])**2 + (coordinates[3] - coordinates[1])**2)**(1/2) distance ((coordinates[2] - coordinates[0])**2 + (coordinates[3] - coordinates[1])**2)**(1/2) (coordinates[2] - coordinates[0])**2 + (coordinates[3] - coordinates[1])**2 (coordinates[2] - coordinates[0])**2 coordinates[2] - coordinates[0] coordinates[2] coordinates 2 coordinates[0] coordinates 0 2 (coordinates[3] - coordinates[1])**2 coordinates[3] - coordinates[1] coordinates[3] coordinates 3 coordinates[1] coordinates 1 2 1/2 1 2 print('{:.5f}'.format(distance)) print '{:.5f}'.format(distance) '{:.5f}'.format '{:.5f}' format distance if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    coordinates = list(map(float, input().split()))
    distance = ((coordinates[2] - coordinates[0])**2 + (coordinates[3] - coordinates[1])**2)**(1/2)
    print('{:.5f}'.format(distance)) def main():
    coordinates = list(map(float, input().split()))
    distance = ((coordinates[2] - coordinates[0])**2 + (coordinates[3] - coordinates[1])**2)**(1/2)
    print('{:.5f}'.format(distance)) main
def main():
    coordinates = list(map(float, input().split()))
    distance = ((coordinates[2] - coordinates[0])**2 + (coordinates[3] - coordinates[1])**2)**(1/2)
    print('{:.5f}'.format(distance))


if __name__ == '__main__':
    main()

